Double-clicking the upper-left corner closed the window, a carryover from earlier versions. I think it still does this, to support programs that auto-click (such as quick and dirty corporate IT apps and such). They couldn't put a single-click control in the same spot.
Also, every app, whether it is hidden or not still responds to Alt+Space which does what the single-click used to do and bring up that old window controls menu, and it still drops down from that same Win 3.x corner. It's a fascinating commitment to a strange backwards compatibility.
(Up until Aero Snap in Vista and it's keyboard shortcuts of Win+Arrow Key I used to use Alt+Space,M a bunch because it was always the easiest way to move any window by keyboard in the event it got stuck somewhere out of mouse range or you just didn't feel like switching to mouse.)
It's also a handy way to get a window that got moved off screen easily, which can happen in setups with multiple monitors that get connected and disconnected.
Also, most applications will actually honor Ctrl+C/V as well as the Ctrl+Insert/Shift+Insert shortcuts, from the 1987 IBM CUA guidelines[0].
